Add development tools: .NET SDKs, Cursor IDE, and AI CLI tools

- Install .NET SDK 8.0 and 9.0 with Microsoft package repository
- Add Cursor IDE with AppImage installation and desktop shortcut
- Install Claude CLI from GitHub releases
- Install Gemini CLI via npm
- Update sandbox mode handling for Cursor IDE
- Add API key setup instructions for AI CLI tools

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

entrypoint.sh

@@ -41,6 +41,10 @@ if [ "$SANDBOX_CHECK_EXIT_CODE" -ne 0 ]; then
     rm -rf /usr/bin/code
     ln -s /usr/share/code/bin/code /usr/bin/code
     sed -i 's|ELECTRON_RUN_AS_NODE=1 "\$ELECTRON" "\$CLI" "\$@"|ELECTRON_RUN_AS_NODE=1 "\$ELECTRON" "\$CLI" --no-sandbox --disable-gpu "\$@"|' /usr/share/code/bin/code
+    # cursor also needs no-sandbox mode
+    if [ -f /opt/cursor/cursor ]; then
+        sed -i 's|exec "\$HERE/cursor"|exec "\$HERE/cursor" --no-sandbox --disable-gpu|' /opt/cursor/cursor 2>/dev/null || true
+    fi
 fi
 set -e